Bad beef will have a sheen to it, like slime coating that is iridescent in the light. And a very pungent odor! If you had to get yoru nose very close it it to smell anything, it's just fine. Go ahead and use it. BTW: aged beef is refrigerated for 30 days at least after slaughter.
High CPK levels are an indicator of a variety of muscle diseases and problems, not just Rhabdo. The 'normal' CPK levels are between 25 and 170. Over this number, and you have muscle cell damage happening. You can have high(er) CPK levels and not have Rhabdomyolysis. You can have muscle cell death happening, and never get to Rhabdomyolosis. You have to have -enough- cell death and -enough- myoglobin and other toxic dead cell byproducts to overwheml the system.
- progressive deterioration of nerve cells and of mental/physical abilities that begins around 6 months of age and usually results in death by 4. - harmful quantities of cell membrane AKA gangliosides accumulate in the nerve cells, which leads to the death of the cells. - muscle stiffness, blindness, deafness, paralytic, motor skill deterioration.